Ammunition cartridges have been made from composite components, commonly a plastic case and a metallic base assembled together. The base and case must have sufficient integrity to withstand the explosive force of the igniting powder in the case when the bullet is fired out of the cartridge and its subsequent extraction from the firing chamber.
The single use nature of ammunition cartridges dictates the desire to have a structurally sound cartridge that is expeditiously made at a low cost.